Hybrid vehicles are attracting attention as environment-friendly vehicles. A hybrid vehicle incorporates a power storage device, an inverter, and an electric motor driven by the inverter, in addition to a conventional internal combustion engine, as the power source for traction.
Japanese Patent Laying-Open No. 2009-166513 (PTL 1) discloses the method for suppressing overdischarge of a power storage device reliably in such a hybrid vehicle. This hybrid vehicle is switched between an HV running mode and an EV running mode according to the required driving force based on the output from various sensors. When there is a switching request to the HV running during execution of the EV running mode, the engine is cranked by a motor generator receiving electric power from the power storage device to start the engine. A discharge allowable power Wout is provided such that the voltage of the power storage device does not become lower than the lower limit voltage, and a torque command value Tref is adjusted such that the motor consumption power does not exceed the provided discharge allowable power Wout. When the accelerator pedal position reaches a predetermined reference value within a predetermined period of time from requesting switching to the HV running mode, the lower limit voltage is temporarily raised.
According to this hybrid vehicle, the power storage device can reliably be protected from overdischarge. As a result, the charging/discharging capability of the power storage device can be exhibited sufficiently to allow the running performance and fuel consumption performance of the vehicle to be improved (refer to PTL 1).